This invention relates to a device and method for detecting the presence and measuring the amount and activity of airborne bacterial contamination.
There is always a concern about airborne contaminants, especially pathogenic bacteria. Consequently, there is a constant need for ambient air monitoring in conjunction with manufacturing and packaging of food, pharmaceutical products, hospital environments and other industrial and clinical facilities. Lately, with the introduction and spread of biological warfare this ambient monitoring issue is becoming critical in a variety of situations.
Prior testing devices perform qualitative and quantitative analyses of ambient air contamination by microorganisms. All of the known devices in the prior art employ an impeller to draw in contaminated air and to cause the microrganisms to be impacted against solidified culture medium. The most successful types of samplers have been the slit-to-agar (STA) devices that utilize a revolving agar plate under a split-type orifice, to impinge the air sample directly upon a nutrient-collecting medium of solidified agar. Viable microorganisms immediately find nutrients suitable for their growth in the collection medium. Such devices are disclosed in U.S. Pat. Nos. 5,500,369 and 5,831,182. However, the test results of these air samplers have been inconsistent. This is due to the basic assumption of the tests that the collected bacteria are equally distributed in the tested atmosphere. However, testing a small portion of air in a large room may result in false negative determinations. Unfortunately these devices cannot sample large portions of air since the agar surfaces can easily dry by the long exposure to the air stream and consequently turn ineffective in growing the microorganisms.
Furthermore, prior art samplers are very difficult to completely sanitize. Cross contamination of samples can easily occur, and accumulation of particulate matter can jeopardize the critical measurements. Sanitation of the prior art samplers and their components is very time consuming and labor intensive and as such a great demand on the operators. Only professionals can actually ensure reliable operation and interpretation of results generated by these devices.
The new apparatus and method for collecting and detecting airborne microorganisms comprises a culturing container containing liquid media capable of growing the suspect microorganisms and a pump for drawing an air sample containing the suspect microorganisms through the liquid media. The suspect microorganisms mix with the liquid media and are subsequently incubated to promote their growth and cause an indication of their presence.
Accordingly, among the several objects and advantages of my invention are to provide a small and portable device that can sample any amount of air in an accumulative manner. The device can be operated with a small rechargeable battery and can be applied in tight places. Most of its components are disposable in order to minimize or completely eliminate sterilization processes. Consequently, the device is easy to operate and does not require highly trained professional personnel for its normal operation. The shelf life of the chemical ingredients are considerably increased because evaporation is not significant during storage. Due to its size and the simplicity of its operation the disclosed device can be used in remote areas where warfare contamination is expected.
Still further objects and advantages will become apparent from a consideration of the ensuing description and accompanying drawings.